Ankle Brachial Pressure Index - The ratio of blood pressure at the ankle to that in the arm. This ratio provides a measure of the degree of arterial disease in the legs, where a value of 1.0 indicates that there is no reduction in blood supply to the legs, compared with the anus. A ratio of 0.9, 0.8, or lower indicates reduced blood supply to the lower limbs.

Absolute risk measures the size of a risk in a person or group of people. This could be the risk of developing a disease over a certain period or it could be a measure of the effect of a treatment, for example how much the risk is reduced by treatment in a person or group. There are different ways of expressing absolute risk. For example, someone with a 1 in 10 risk of developing a certain disease has ‘a 10% risk’ or ‘a 0.1 risk’, depending on whether percentages or decimals are used. Absolute risk does not compare changes in risk between groups, for example risk changes in a treated group compared to risk changes in an untreated group. That is the function of relative risk.

The difference in the rate of outcomes between the control group of a study and the intervention group. For example, if 30% of people experience a serious event in the control group and 20% in the intervention group, the ARR is 10% (30%-20%).

A chronic acne involving mainly the face, chest, and shoulders that is common in adolescent humans and is characterised by the intermittent formation of discrete papular or pustular lesions often resulting in considerable scarring

A naturally occurring chemical produced in the body in response to stress. When given as a drug it causes increases in heart rate and blood pressure. Adrenaline is also used as a treatment for severe allergic reaction.

Dementia can cause people to see or hear things that are not there, but more often if a person talks about things that aren’t there it is because he has misinterpreted sights or sounds in the environment, such as shadows, mirrors, patterns on the
carpet, or noise from the television

The part of the body through which the air passes on its way to the lungs. The ‘upper airway’ usually refers to the mouth and throat as far down as the voice-box (larynx); the ‘lower airway’ refers to the air passages below the larynx. ‘Airway’ also refers to a tube placed through the mouth or nose to facilitate the free movement of air, oxygen, or anaesthetic gases.

crease across the bridge of the nose caused by allergic salute (a mannerism seen in allergy, where the nose is repeatedly pushed upward with the palm of the hand in an attempt to reduce nasal obstruction).

This is a process used in studies that involve different groups receiving different interventions or treatment. Ideally, allocation to the different groups is done in such a way that the participants, and the health care providers, do not know which intervention the participant is to receive. The intention is to avoid bias during the allocation process so that the intervention and control groups are as similar as possible.

The Alzheimer’s Disease Assessment Scale (ADAS) of which one section is the ADAS Cog, evaluates cognitive functions affected in Alzheimer’s disease including memory, language and praxis. This 11-part test is more thorough than the MMSE and can be used for people with mild symptoms. It is a commonly used for brief examination of memory and language skills and is often used as a measure in clinical drug trials. It takes around 30 minutes and can be conducted by several members from the multidisciplinary team (such as a doctor, nurse, OT or psychologist)

Alzheimer's disease is the most common cause of dementia. It was first described by the German neurologist Alois Alzheimer, is a physical disease affecting the brain. During the course of the disease, 'plaques' and 'tangles' develop in the structure of the brain, leading to the death of brain cells. People with Alzheimer's also have a shortage of some important chemicals in their brains. These chemicals are involved with the transmission of messages within the brain.

Alzheimer's is a progressive disease, which means that gradually, over time, more parts of the brain are damaged. As this happens, the symptoms become more severe. People in the early stages of Alzheimer's disease may experience lapses of memory and have problems finding the right words. As the disease progresses, they may:
• become confused, and frequently forget the names of people, places, appointments and recent events
• experience mood swings. They may feel sad or angry. They may feel scared and frustrated by their increasing memory loss
• become more withdrawn, due either to a loss of confidence or to communication problems.
As the disease progresses, people with Alzheimer's will need more support from those who care for them. Eventually, they will need help with all their daily activities.
[adapted from Alzheimer’s Society website]

The Alzheimer's Society is the UK's leading care and research charity for people with dementia and those who care for them. The Alzheimer's Society was formed back in 1979, when two people with extensive experience of caring for loved ones with dementia discussed the pressing need to raise awareness of dementia and to improve the quality of care, support and information for people with dementia and their carers.

This led to the creation of the 'Alzheimer's Disease Society'. and the first branches were established in Oxford and Bromley in 1980 and 1981 respectively. Through the eighties and nineties the Society continued to grow, with volunteer committees establishing branches across England, Wales and Northern Ireland. At the AGM in 1999 members of the Society agreed the change of name to 'Alzheimer's Society'.

By 2003 the Society was a £30million organisation, with over 250 branches across England, Wales and Northern Ireland.

Loss of sensation and usually of consciousness without loss of vital functions, artificially produced by the administration of one or more agents that block the passage of pain impulses along nerve pathways to the brain

The written or computer generated record of the process and events of a particular anaesthetic. Details noted include drugs and doses; measurements such as heart rate and blood pressure; amount (or percentage) of oxygen delivered; fluids given and blood lost; and surgical events.

Data analysis involves examining and processing research data, in order to answer the questions that the project is trying to address. It involves identifying patterns and drawing out the main themes, and is often done with specialist computer software.

Loss of sensation and usually of consciousness without loss of vital functions, artificially produced by the administration of one or more agents that block the passage of pain impulses along nerve pathways to the brain

(ABPI) The ratio of blood pressure at the ankle to that in the arm. This ratio provides a measure of the degree of arterial disease in the legs, where a value of 1.0 indicates that there is no reduction in blood supply to the legs, compared with the anus. A ratio of 0.9, 0.8, or lower indicates reduced blood supply to the lower limbs.

Fusion of the bones across a joint space, either by bony tissue or by shortening of connecting fibrous tissue. Ankylosis is a complication of prolonged joint inflammation, as may occur in chronic infection or rheumatic disease.

Anti-inflammatory drugs are drugs that reduce inflammation. This includes substances produced by the body itself like cortisone. It also includes artificial substances like ASA – acetylsalicylic acid (or “aspirin”) or ibuprofen –, which relieve pain and reduce fever as well as reducing inflammation.

A drug that decreases the ability of the blood to clot. Blood clots (thromboses) in the veins can damage blood flow. If blood clots move through the circulation they can block the blood flow through a major blood vessel.

Also referred to as dyspraxia, apraxia is neurological disorder characterized by loss of the ability to execute or carry out learned purposeful movements, despite having the desire and the physical ability to perform the movements.

Aricept (donepezil hydrochloride) is a cholinesterase inhibitor. It is produced by Eisai and co-marketed with Pfizer and was the first drug to be licensed in the UK specifically for Alzheimer's disease

The difference in the rate of outcomes between the control group of a study and the intervention group. For example, if 30% of people experience a serious event in the control group and 20% in the intervention group, the ARR is 10% (30%-20%).

The atopic march refers to the natural history of allergic or atopic manifestations characterised by a typical sequence of clinical symptoms and conditions appearing during a certain age period and persisting over a number of years (Weinberg, EG. Current Allergy & Clinical Immunology, March 2005 Vol 18, No. 1)

A before and after study measures particular characteristics of a population or group of individuals at the end of an event or intervention and compares them with those characteristics before the event or intervention. The study gauges the effects of the event or intervention.

A fixed prosthesis to replace one or more missing teeth, to restore the function, form or aesthetics of the mouth. It is also known as a fixed/non-removable partial denture. Bridges are supported and held in position by attachments to adjacent or remaining teeth [see Resin-bonded Bridges].

Also known as CPR - A procedure designed to restore normal breathing after cardiac arrest that includes the clearance of air passages to the lungs, the mouth-to-mouth method of artificial respiration, and heart massage by the exertion of pressure on the chest

A carer is a relative, friend or partner who provides (or intends to provide, or used to provide) a substantial amount of care to another person on a regular basis, but not necessarily through living with them.

Case crossover studies look at the effects of factors that are thought to increase the risk of a particular outcome in the short term. For example, this type of study might be used to look at the effects of changes in air pollution levels on the short-term risk of asthma attacks. Individuals who have had the outcome of interest are identified and act as their own control.
The presence or absence of the risk factor is assessed for the period immediately before the individual experienced the outcome. This is compared with the presence or absence of the risk factor when the individual did not experience the outcome (control period). If there is a link between the risk factor and the outcome, it would be expected to have been present in the period just before the outcome more often than in the control period.

A case series is a descriptive study of a group of people, who usually receive the same treatment or who have the same disease. This type of study can describe characteristics or outcomes in a particular group of people, but cannot determine how they compare with people who are treated differently or who do not have the condition.

A case-control study is an epidemiological study that is often used to identify risk factors for a medical condition. This type of study compares a group of patients who have that condition with a group of patients that do not have it, and looks back in time to see how the characteristics of the two groups differ.

Identifying features of a healthcare study that can be assessed to give a measure of its quality. These include the design of the study, participants, setting, interventions used, and the outcomes monitored and follow-up of the people who were initially assigned to the study.

Marked by long duration, by frequent recurrence over a long time, and often by slowly progressing deterioration; having a slow progressive course of indefinite duration. Examples of chronic wounds are pressure ulcers, leg ulcers and diabetic foot ulcers. (cf: acute).

A confidence interval (CI) expresses the precision of an estimate and is often presented alongside the results of a study (usually the 95% confidence interval). The CI shows the range within which we are confident that the true result from a population will lie 95% of the time. The narrower the interval, the more precise the estimate. There is bound to be some uncertainty in estimates because studies are conducted on samples and not entire populations.
By convention, 95% certainty is considered high enough for researchers to draw conclusions that can be generalised from samples to populations. If we are comparing two groups using relative measures, such as relative risks or odds ratios, and see that the 95% CI includes the value of one in its range, we can say that there is no difference between the groups. This confidence interval tells us that, at least some of the time, the ratio of effects between the groups is one. Similarly, if an absolute measure of effect, such as a difference in means between groups, has a 95% CI that includes zero in its range, we can conclude there is no difference between the groups.

An opening in the upper lip between the mouth and the nose, it can range from a slight notch in the coloured portion of the lip to complete seperation in one or both sides of the kip extending up and into the nose.

Clinical trials are research studies involving people who use services, which compare a new or different type of treatment with the best treatment currently available. They test whether the new or different treatment is safe, effective and any better than what already exists. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known.

It is a simple bedside test that is independent of bias due to intellect, language or cultural factors. The clock drawing test does not detect early cognitive changes or discriminate between types of dementia raising questions about its suitability to be used in isolation.

There are a number of alternative ways of administering and scoring the CDT, such as those described by, Shulman (1993), Sunderland (1989) and Wolf-Klein (1989). Of these, the Shulman method has been found to be the most sensitive and specific screening test for mild-moderate dementia when used in conjunction with MMSE.

In the Shulman method, subjects are asked to add the numbers of a clock-face on to a pre-drawn circle and to mark in the hands to resemble a specified time. Results are scored as follows:

One of the databases in The Cochrane Library. It brings together all the currently available reviews and protocols for Cochrane Reviews. It is updated quarterly, and is available via the Internet and CD-ROM.

A registered collaborative review group of the Cochrane Collaboration, dedicated to producing systematic reviews about interventions to prevent or treat dementia, and also reviews of diagnostic test accuracy in dementia

Cognitive abilities are the brain-based skills and mental processes that are needed to carry out any task -from the simplest to the most complex. Every task can be broken down into the different cognitive skills that are needed to complete that task successfully.

Also known as paper and pencil tests. These type of tests cannot diagnose dementia as they test limited domains of cognition. They can be useful in identifying someone needing further investigation and are also useful if done serially to map any change in cognition over time.

A population group identified for study. They are clearly defined by factors such as the region in which they live, or the likelihood of an event. This term can also be used to describe a study type ie a cohort study.

This study identifies a group of people and follows them over a period of time to see how their exposures affect their outcomes. This type of study is normally used to look at the effect of suspected risk factors that cannot be controlled experimentally, for example the effect of smoking on lung cancer.

The result of an operation, usually for bowel cancer, in which the lower end of the bowel is relocated to an artificial opening on the front of the abdomen. Faeces are collected into a special plastic bag and emptied as necessary.

This is a process used in studies that involve different groups receiving different interventions or treatment. Ideally, allocation to the different groups is done in such a way that the participants, and the health care providers, do not know which intervention the participant is to receive. The intention is to avoid bias during the allocation process so that the intervention and control groups are as similar as possible.

(or 'CI) The range within which the true size of effect of a treatment or intervention is found (never exactly known) with a given
degree of assurance. A 95 percent confidence interval is the interval which includes the true value in 95 percent of cases

A confidence interval (CI) expresses the precision of an estimate and is often presented alongside the results of a study (usually the 95% confidence interval). The CI shows the range within which we are confident that the true result from a population will lie 95% of the time. The narrower the interval, the more precise the estimate. There is bound to be some uncertainty in estimates because studies are conducted on samples and not entire populations.
By convention, 95% certainty is considered high enough for researchers to draw conclusions that can be generalised from samples to populations. If we are comparing two groups using relative measures, such as relative risks or odds ratios, and see that the 95% CI includes the value of one in its range, we can say that there is no difference between the groups. This confidence interval tells us that, at least some of the time, the ratio of effects between the groups is one. Similarly, if an absolute measure of effect, such as a difference in means between groups, has a 95% CI that includes zero in its range, we can conclude there is no difference between the groups.

A confounder can distort the true relationship between two (or more) characteristics. When it is not taken into account, false conclusions can be drawn about associations. An example is to conclude that if people who carry a lighter are more likely to develop lung cancer, it is because carrying a lighter causes lung cancer. In fact, smoking is a confounder here. People who carry a lighter are more likely to be smokers and smokers are more likely to develop lung cancer.

A factor to consider when looking at the association between exposure to a cause (or risk factor) and the occurrence of disease. Age groups and sex are common confounding factors as they may be associated with some exposures. Further, the more likely he or she is to develop certain diseases.

A confounder can distort the true relationship between two (or more) characteristics. When it is not taken into account, false conclusions can be drawn about associations. An example is to conclude that if people who carry a lighter are more likely to develop lung cancer, it is because carrying a lighter causes lung cancer. In fact, smoking is a confounder here. People who carry a lighter are more likely to be smokers and smokers are more likely to develop lung cancer.

The term consumer is used to refer collectively to:
• people who use services
• carers
• organisations representing consumers’ interests
• members of the public who are the potential recipients of services
• groups asking for research to promote good health or because they believe they have been exposed to potentially harmful circumstances, products or services.

The group in a study that does not receive the intervention that is being investigated. Controls may receive no intervention, a placebo, a commonly used treatment for that condition, or only a part of an intervention.

A cost-benefit analysis is an evaluation which places a monetary value on benefits or outcomes. The costs and benefits are often expressed in dollar terms and examined to find out whether the benefits outweigh the costs.

Cost-effectiveness analysis is a comparative technique. Two or more health programmes, or programme options, are compared in terms of the cost per unit of output (eg, cost per cancer detected) or cost per unit of outcome (eg, cost per life saved, cost per year of life saved, cost per quality-adjusted year of life saved). Rarely described in randomized studies.

Cardiopulmonary resuscitation - A procedure designed to restore normal breathing after cardiac arrest that includes the clearance of air passages to the lungs, the mouth-to-mouth method of artificial respiration, and heart massage by the exertion of pressure on the chest

A form of seborrheic dermatitis of the scalp in infants that is characterised by flaky or scaly skin which may be reddened. May involve the skin on the nose, eyebrows, scalp, ears, and skin of the trunk (in skin folds)

Relating to, indicating, or being the stage of a disease at which an abrupt change for better or worse may be anticipated with reasonable certainty; being or relating to an illness or condition involving danger of death

This is an epidemiological study that describes characteristics of a population. It is ‘cross sectional’ because data is collected at one point in time and the relationships between characteristics are considered. Importantly, because this study doesn’t look at time trends, it can’t establish what causes what.

D

Data is the information collected through research. It can include written information, numbers, sounds and pictures. It is usually stored on computer, so that it can be analysed, interpreted and then communicated to others, for example in reports, graphs or diagrams.

The process of cleaning an open wound by removal of foreign material and dead tissue so that healing may occur without hindrance. In dentistry, it refers to the necessary removal of plaque and calculus that have accumulated on the teeth in order to maintain oral health.

Clotting and inflammation of the veins, usually in the calves of the legs. There is a risk that some of the clot may dislodge and travel in the bloodstream back to the heart and lungs, where it may cause major blockage of the blood flow. DVT is more common in the elderly, females, smokers, obese patients, and those having major surgery for cancer. Prevention is mainly by the use of anti-clotting agents and having the patent get out of bed and start walking around as soon as possible after the operation.

Dementia is a syndrome (a group of related symptoms) that is associated with a progressive decline in mental functions and abilities. For example:
• memory,
• thinking,
• language,
• understanding, and
• judgement.
People with dementia may also have problems controlling their emotions, experience changes in their personality, and behave inappropriately in social situations. Most cases of dementia are caused by damage to the structure of the brain.
How common is dementia?
Dementia is a common condition. For example, in England, there are currently over half a million people living with dementia, and that number is expected to double over the next 30 years. Most cases of dementia develop in people who are 65 years of age, or over. You are also more likely to develop dementia the older you are.
Types of dementia
There are many different types of dementia. The most common types of dementia
are listed below.
• Alzheimer's disease -where small clumps of protein, known as plaques, begin to develop around brain cells, disrupting the normal workings of the brain.
• Vascular dementia -where underlying problems with blood circulation result in parts of the brain not receiving enough blood and oxygen.
• Dementia with Lewy bodies -where abnormal structures, known as Lewy bodies, begin to develop inside the brain.
• Frontotemporal dementia -where parts of the brain, known as the frontal and temporal lobes, begin to shrink. Unlike other types of dementia, frontotemporal dementia usually develops in people who are under 65.
years of age. It is also much rarer than other types of dementia.

Dementia with Lewy bodies (DLB) is a form of dementia that shares characteristics with both Alzheimer's and Parkinson's diseases. It accounts for around four per cent of all cases of dementia in older people. Dementia with Lewy bodies is sometimes referred to by other names, including Lewy body dementia, Lewy body variant of Alzheimer's disease, diffuse Lewy body disease, cortical Lewy body disease and senile dementia of Lewy body type. All these terms refer to the same disorder. This factsheet outlines the symptoms of DLB, how it is diagnosed and how it is treated. DLB appears to affect men and women equally. As with all forms of dementia, it is more prevalent in people over the age of 65. However, in certain rare cases people under 65 may develop DLB.
• They may experience problems with attention and alertness, often have spatial disorientation and experience difficulty with 'executive function', which includes difficulty in planning ahead and co-ordinating mental activities. Although memory is often affected, it is typically less so than in Alzheimer's disease.
• They may also develop the symptoms of Parkinson's disease, including slowness, muscle stiffness, trembling of the limbs, a tendency to shuffle when walking, loss of facial expression, and changes in the strength and
tone of the voice.
There are also symptoms that are characteristic of DLB. In addition to the symptoms above, a person with DLB may:
• experience detailed and convincing visual hallucinations (seeing things that are not there), often of people or animals
• find that their abilities fluctuate daily, or even hourly
• fall asleep very easily by day, and have restless, disturbed nights with confusion, nightmares and hallucinations
• faint, fall, or have 'funny turns'.
[adapted from Alzheimer’s Society website]

The defective formation of parts of the tooth due to illnesses such as measles or starvation while the tooth is being formed. It is marked by transverse lines of brown defective enamel, which define the date of the illness.

Pain arising from exposed dentine (the calcified organic tissue of the tooth, usually covered by the harder outer enamel layer), typically in response to external stimuli (such as hot or cold foods or drinks or cold air), and which cannot be explained by any other form of dental disease.

A diagnostic study tests a new diagnostic method to see if it is as good as the ‘gold standard’ method of diagnosing a disease. The diagnostic method may be used when people are suspected of having a disease because of signs and symptoms, or to try and detect a disease before any symptoms have developed (a screening method).

Dissemination involves communicating the findings of a research project to a wide range of people who might find it useful. This can be done through:
• producing reports (often these are made available on the Internet)
• publishing articles in journals or newsletters
• issuing press releases
• giving talks at conferences.
It is also important to feedback the findings of research to research participants.

When significant areas of skin are damaged, for example in burns, then a skin graft is one treatment. The skin graft is taken from an area of healthy skin, e.g. the thigh or stomach and the acute wound caused is called the donor site.

Term used to describe a study in which both the investigator or the participant are unaware of the nature of the treatment the participant is receiving. Double-blind trials are thought to produce objective results, since the expectations of the researcher and the participant about the experimental treatment such as a drug do not affect the outcome.

There are two main types of drugs used to treat Alzheimer's disease. Aricept, Exelon and Reminyl all work in a similar way, and are known as acetylcholinesterase inhibitors. Ebixa works in a different way to the other three.
• Aricept (donepezil hydrochloride), produced by Eisai and co-marketed with Pfizer, was the first drug to be licensed in the UK specifically for Alzheimer's disease.
• Exelon (rivastigmine), produced by Novartis Pharmaceuticals, was the second drug licensed in the UK specifically for Alzheimer's disease.
• Reminyl (galantamine) was co-developed by Shire Pharmaceuticals and the Janssen Research Foundation. Originally derived from the bulbs of snowdrops and narcissi, it was the third drug licensed in the UK specifically
for Alzheimer's disease.
• Ebixa (memantine) is produced by Merz and marketed in Europe by Lundbeck. It is the newest of the Alzheimer's drugs.

Clotting and inflammation of the veins, usually in the calves of the legs. There is a risk that some of the clot may dislodge and travel in the bloodstream back to the heart and lungs, where it may cause major blockage of the blood flow. DVT is more common in the elderly, females, smokers, obese patients, and those having major surgery for cancer. Prevention is mainly by the use of anti-clotting agents and having the patent get out of bed and start walking around as soon as possible after the operation.

A bruise: an initially bluish-black mark on the skin, resulting from the release of blood into the tissues either through injury or through the spontaneous leaking of blood from the vessels (as in some blood diseases).

The extent to which a specific intervention, procedure, regimen or service produces a beneficial result under ideal conditions, e.g. the determination of efficacy of CRC screening is based on the results of a randomised controlled trial (with CRC mortality as the outcome measure).

The criteria that are clearly set out beforehand to define whether a potential participant is eligible to enter a study. In the Cochrane context, this term refers to the criteria that are clearly set out beforehand to define whether a study meets the requirements for inclusion in a systematic review.

The phase of anaesthesia during which patients ‘emerge’ from the anaesthetised state to regain at least some control over their functions. After emergence, patients are transferred to a special area where continued recovery occurs under the care of a nurse, as delegated by the anaesthetist.

A visual examination of internal surface structures of the body with a flexible tubular instrument with light. Colonoscopy, Sigmoidoscopy and Proctoscopy are endoscopic examinations of the colon and rectum.

Adrenaline, a naturally occurring chemical produced in the body in response to stress. When given as a drug it causes increases in heart rate and blood pressure. Adrenaline is also used as a treatment for severe allergic reaction.

Epidural anaesthesia refers to the placement of drugs into the epidural space. This is the space that surrounds the spinal cord and its covering layers, through which the spinal nerves pass as they connect to other nerves leading to and from all parts of the body.

swelling and inflammation (usually bacterial infection) of the epiglottis (the thin flap of cartilage covering the entrance of the air passage, during swallowing, thereby preventing the food etc. going into the lungs), obstructing air flow to the lungs

Ethics are a set of principles that guide researchers who are carrying out research with people. Ethical principles are designed to protect the safety, dignity, rights and well-being of the people taking part. They include the requirement to ask each individual to give their informed consent to take part in a research project.

This involves assessing whether an intervention (for example a treatment, service, project, or programme) is achieving its aims. A project can be evaluated as it goes along or right at the end. An evaluation can measure how well the project is being carried out as well as its impact. The results of evaluations can help with decision-making and planning.

An experiment is any study in which the conditions are under the direct control of the researcher. This usually involves giving a group of people an intervention that would not have occurred naturally. Experiments are often used to test the effects of a treatment in people and usually involve comparison with a group who do not get the treatment.

Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store iron in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (Apoferritins) made of 24 subunits of various sequences depending on the species and tissue types

An impermeable material that is bonded to the occlusal (chewing) surface of posterior teeth to seal the fine grooves (fissures) and pits in the enamel surface of the tooth, to prevent dental caries (dental decay).

A graphical representation, as seen on the Cochrane logo, of the result of pooling data from a number of healthcare studies. These look at an outcome from an intervention in a clearly defined healthcare situation and the vertical line in the middle is the point at which the intervention under investigation and the control have the same effect.

The Frontal Assessment Battery is a brief tool that can be used at the bedside or in a clinic setting to assist in discriminating between dementias with a frontal dysexecutive phenotype and Dementia of Alzheimer’s Type (DAT). The FAB has validity in distinguishing Fronto-temporal type dementia from DAT in mildly demented patients (MMSE > 24). Total score is from a maximum of 18, higher scores indicating better performance

The term 'fronto-temporal dementia' covers a range of conditions, including Pick's disease, frontal lobe degeneration, and dementia associated with motor neurone disease. All are caused by damage to the frontal lobe and/or the temporal parts of the brain. These areas are responsible for our behaviour, emotional responses and language skills. Damage to the frontal and temporal lobe areas of the brain causes a variety of
different symptoms. Each person will experience the condition in his or her own individual way, but there are some symptoms commonly experienced by people with the condition. Typically, during the initial stages of fronto-temporal dementia, the person's memory is still intact but their personality and behaviour changes. People with frontotemporal dementia may:
• lack insight, and lose the ability to empathise with others. This can make them appear selfish and unfeeling
• become extrovert when they were previously introverted, or withdrawn when they were previously outgoing
• behave inappropriately -for example, making tactless comments, joking at the 'wrong' moments, or being rude.
• lose their inhibitions -for example, exhibiting sexual behaviour in public
• become aggressive
• be easily distracted
• develop routines -for example, compulsive rituals.
The person with fronto-temporal dementia may also experience language difficulties, including:
• problems finding the right words
• a lack of spontaneous conversation
• circumlocution, using many words to describe something simple
• a reduction in or lack of speech.
[adapted from Alzheimer’s Society website]

A term used to describe the potential for the stomach to have failed to empty properly before anaesthetic is started. This is most common in cases where the bowel is obstructed, or the patient has been involved in an accident (even a minor one) between the time of last eating and the time of surgery.

This study looks across the entire genetic sequence (genome) to identify variations in this sequence that are more common in people with a particular characteristic or condition and that may be involved in producing that characteristic or condition.

The Geriatric Depression Scale is commonly used to screen mood disorder which may impact on performance of other cognitive assessments. A score of 5 or more is suggestive of an underlying mood disorder and further clinical assessment is recommended.

There has been some concern about its accuracy in detecting minor depression. It is suitable for use with people with a Mini-Mental Status score of more than 14. It takes 5-10 minutes to complete.

Huntington's disease (also referred to in more formal medical research as Huntington Disease) is an hereditary neurological disorder of the central nervous system that causes progressive degeneration of cells in the brain, slowly impairing a person's ability to walk, think, talk and reason. It was first described in 1872 by an American doctor, George Huntington, who studied an extended family in Long Island affected by the condition.
Symptoms develop gradually over months or years. The age at which they first appear is usually between about 30 and 50. However, in about 5% of cases Huntington's disease becomes apparent before the age of 20 (in this situation, referred to as juvenile-onset Huntington's Disease, it is usually inherited from the father). The onset and rate of progression of the disease tends to follow a pattern within each family. Symptoms begin with memory loss (especially of recent events) or confusion, changes in personality and mood that may include aggressive and antisocial behaviour, as well as clumsiness or uncontrolled muscle movements (these movements are known as chorea) and rigidity. As the condition progresses, other symptoms of dementia appear, such as loss of rational thought and poor concentration. Involuntary movements, difficulties with
speaking and swallowing, weight loss, seizures, depression and anxiety may also occur. The disease often progresses slowly, and the affected person may live for 15 to 20 years after the initial diagnosis.

A widening of the normal space between the abdomen and the chest through which the oesophagus passes. As a result, part of the stomach slides into the chest, and acid from the stomach is able to flow up the oesophagus, causing ‘heartburn’ (indigestion).

This is a hierarchical categorisation (ranking) of different types of clinical evidence. It is partly based on the type of study involved and ranks evidence according to its ability to avoid various biases in medical research. Several ranking schemes exist that are specific to the question posed in the research. Studies with the highest ranking are those that provide the best evidence that a result is true.
Examples of studies ranked in order from high-level to low-level evidence are:
• systematic reviews
• single randomised controlled trials
• controlled trials without randomisation
• prospective cohort studies
• case-control studies
• cross sectional studies
• case series
• single case reports

One of a number of naturally occurring substances transmitting 'messages for action' to different parts of the body. Hormones are produced by endocrine glands/tissues, are secreted into the bloodstream and carried to distant tissues or organs where they act to modify their structure or function.

An excess of glucose (sugar) in the bloodstream. It may occur in a variety of diseases, most notably in diabetes mellitus, due to insufficient insulin in the blood and excessive intake of carbohydrates. Untreated it may progress to diabetic coma.

A rare condition in which, after administration of certain triggering drugs, the patient develops an uncontrollable rise in temperature. The susceptibility is hereditary and the condition is treatable.

1. Impartial: The Cochrane Collaboration's status as a non-governmental and not-for-profit organisation means it operates without bias or influence.
2. Independent: Our independent status helps us maintain the quality of our output at all times - unconstrained by commercial and financial interests.
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The situation where people are entered into a healthcare study, allocated into a group, and then, for whatever reason, do not complete the study. It is important in the analysis of results to consider these people, especially if it is the intervention that led them to stop being involved by withdrawing or ‘dropping out’.

Or 'IV'. Into the vein, by injection. Sometimes the word ‘intravenous’ refers to a cannula inserted into a vein as a means of injecting drugs intravenously. The cannula may or may not have a fluid infusion or intravenous line attached.

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) is a questionnaire that can be filled out by a relative or carer (the informant) of an older person to determine whether that person has declined in cognitive functioning. The IQCODE is often used as a screening test for dementia.

IQCODE is especially useful in cases where, for different reasons, a meaningful formal cognitive assessment cannot be performed. It also gives the relative an opportunity to say what they feel. IQCODE has been found to have similar specificity and sensitivity to the MMSE.

Most screening tests for dementia involve a brief list of questions to directly assess cognitive functioning, such as the MMSE. A disadvantage of such tests is that they are affected by the person’s level of education, familiarity with the dominant language and culture in their country, and level of intelligence before the onset of dementia. Because of this, cognitive screening tests can falsely indicate dementia in people with lower education, culturally and linguistically diverse backgrounds, and lower intelligence. The IQCODE attempts to overcome this problem by assessing change from earlier in life, rather than the person’s current level of functioning. It does this by making use of the informant’s knowledge of both the person’s earlier and current cognitive functioning.

Stands for 'intravenous'. Into the vein, by injection. Sometimes the word ‘intravenous’ refers to a cannula inserted into a vein as a means of injecting drugs intravenously. The cannula may or may not have a fluid infusion or intravenous line attached.

'LMA'. A device used to connect the breathing circuit to the patients trachea without passing a tube through the larynx (voice-box). The LMA consists of a tube with an inflatable pad that encloses the larynx.

A device used to insert an endotracheal tube into the trachea. The laryngoscope consists of a long metal ‘blade’ with a light, which is inserted into the mouth of the anaesthetised patient so the anaesthetist can see the larynx.

part of the throat responsible for the production of vocal sounds; also serving as passage for air travelling into the lungs. It is made up of a framework of cartilage, within which the vocal cords are situated.

Screening advances the date of diagnosis, thereby extending the interval between diagnosis and death, even if the time of death is unchanged. In screened individuals, diagnosis is made earlier than it would have been in the absence of screening; this is known as the 'lead time' obtained by screening. The survival time is measured from time of diagnosis until time of death; individuals diagnosed on screening will have longer survival times, even if screening had no effect on their time of death.

Tumours grow at different rates. With each screening round, the probability of detecting slow-growing tumours is greater than that of detecting fast-growing tumours, because slower growing tumours remain in the pre-symptomatic screen-detectable phase for longer. Thus, there will be fewer fast-growing tumours in a screened group compared with an unscreened group. Slow-growing tumours tend to have a better prognosis, which may account for differences in outcome between the groups.

Dementia with Lewy bodies (DLB) is a form of dementia that shares characteristics with both Alzheimer's and Parkinson's diseases. It accounts for around four per cent of all cases of dementia in older people. Dementia with Lewy bodies is sometimes referred to by other names, including Lewy body dementia, Lewy body variant of Alzheimer's disease, diffuse Lewy body disease, cortical Lewy body disease and senile dementia of Lewy body type. All these terms refer to the same disorder. This factsheet outlines the symptoms of DLB, how it is diagnosed and how it is treated. DLB appears to affect men and women equally. As with all forms of dementia, it is more prevalent in people over the age of 65. However, in certain rare cases people under 65 may develop DLB.
• They may experience problems with attention and alertness, often have spatial disorientation and experience difficulty with 'executive function', which includes difficulty in planning ahead and co-ordinating mental activities. Although memory is often affected, it is typically less so than in Alzheimer's disease.
• They may also develop the symptoms of Parkinson's disease, including slowness, muscle stiffness, trembling of the limbs, a tendency to shuffle when walking, loss of facial expression, and changes in the strength and
tone of the voice.
There are also symptoms that are characteristic of DLB. In addition to the symptoms above, a person with DLB may:
• experience detailed and convincing visual hallucinations (seeing things that are not there), often of people or animals
• find that their abilities fluctuate daily, or even hourly
• fall asleep very easily by day, and have restless, disturbed nights with confusion, nightmares and hallucinations
• faint, fall, or have 'funny turns'.
[adapted from Alzheimer’s Society website]

A Likert scale is a commonly used rating scale that measures attitudes or feelings on a continuous linear scale, usually from a minimum ‘strongly disagree’ response to a maximum ‘strongly disagree’ response, or similar. Likert-scales can be 5-point, 6-point, 10-point, etc. depending on the number of response options available.

A 'laryngeal mask airway'. A device used to connect the breathing circuit to the patients trachea without passing a tube through the larynx (voice-box). The LMA consists of a tube with an inflatable pad that encloses the larynx.

This is a hierarchical categorisation (ranking) of different types of clinical evidence. It is partly based on the type of study involved and ranks evidence according to its ability to avoid various biases in medical research. Several ranking schemes exist that are specific to the question posed in the research. Studies with the highest ranking are those that provide the best evidence that a result is true.
Examples of studies ranked in order from high-level to low-level evidence are:
• systematic reviews
• single randomised controlled trials
• controlled trials without randomisation
• prospective cohort studies
• case-control studies
• cross sectional studies
• case series
• single case reports

A rare condition in which, after administration of certain triggering drugs, the patient develops an uncontrollable rise in temperature. The susceptibility is hereditary and the condition is treatable.

part of the skull that extends downwards behind the ear canal. It contains many air spaces that communicate with the middle ear via an air-filled channel (providing a possible route for spread of infection from the middle ear).

A way of analysing information or data from a number of different studies to determine an average, or common, effect. It is aimed at improving the precision of the available data by looking at a greater number of people, including from different populations.

'Malignant hyperthermia'. A rare condition in which, after administration of certain triggering drugs, the patient develops an uncontrollable rise in temperature. The susceptibility is hereditary and the condition is treatable.

Devices that measure changes in some aspect of the patient’s condition, such as heart rate, or a piece of equipment – for example, concentration of oxygen delivered from the anaesthetic machine. (A car speedometer is a monitor of road speed.)

N

A drug (as opium) that in moderate doses dulls the senses, relieves pain, and induces profound sleep but in excessive doses causes stupor, coma, or convulsions; a drug (as marijuana or LSD) subject to restriction similar to that of addictive narcotics whether in fact physiologically addictive and narcotic or not

A narrative review discusses and summarises the literature on a particular topic, without generating any pooled summary figures through meta-analysis. This type of review usually gives a comprehensive overview of a topic, rather than addressing a specific question such as how effective a treatment is for a particular condition. Narrative reviews do not often report on how the search for literature was carried out or how it was decided which studies were relevant to include. Therefore, they are not classified as systematic reviews.

This is one of a set of measures used to show the accuracy of a diagnostic test (see sensitivity, specificity and positive predictive value). The negative predictive value (NPV) of a test is a measure of how accurate a negative result on that test is at identifying that a person does not have a disease. The NPV is the proportion of people with a negative test result who do not truly have a disease. For example, if a test has an NPV of 75%, this means that 75% of the people who test negative are truly disease free, while 25% who test negative have the disease (false negatives). The NPV for a test varies depending on how common the disease is in the population being tested. An NPV is usually lower (false negatives are more common) when disease prevalence is higher.

A nested case-control study is a special type of case-control study in which ‘cases’ of a disease are drawn for the same cohort (population of people) as the controls to whom they are compared. These studies are sometimes called case-control studies nested in a cohort or case-cohort studies. The collection of data on the cases and controls is defined before the study begins.
Compared with a simple case-control study, the nested case-control study can reduce 'recall bias' (where a participant remembers a past event inaccurately) and temporal ambiguity (where it is unclear whether a hypothesised cause preceded an outcome). It can be less expensive and time consuming than a cohort study. Incidence and prevalence rates of a disease can sometimes be estimated from a nested case-control cohort study, whereas they cannot from a simple case-control study (as the total number of exposed people (the denominator) and the follow up time are not usually known).

A statistical measure of the number of people who need to be given an intervention in order to observe a beneficial effect for one extra person. It is calculated from the risk difference. It is the inverse of the absolute risk difference

Any one of a large group of drugs used for pain relief. NSAIDs act by inhibiting the cyclo-oxygenase enzymes responsible for controlling the formation of prostaglandins, which are important mediators of inflammation. They include ibuprofen, aspirin, azapropazone and others. Adverse effects include gastric bleeding and ulceration.

A statistical measure of the number of people who need to be given an intervention in order to observe a beneficial effect for one extra person. It is calculated from the risk difference. It is the inverse of the absolute risk difference.

OSA. A condition where partial blockage to breathing in the mouth and at the back of the throat leads to short periods of interruption of breathing while asleep. Such breathing while asleep is noisy, as in snoring.

A rigid or flexible appliance that overlays the occlusal surfaces (where the teeth meet) of the teeth to treat clenching, grinding and its associated consequences. It can also provide temporary relief from muscle or Temporomandibular Joint pain.

Odds Ratio (OR): The ratio of the odds of an event in the experimental (intervention) group to the odds of an event in the control group. If 100
persons have an event rate of 0.20, then 20 persons have the event and 80 persons do not. The OR will be 20/80 or 0.25. Value 1.00 indicates no differences between the two groups.

An odds ratio is one of several ways to summarise the association between an exposure and an outcome, such as a disease. (Another commonly used approach is to calculaterelative risks.)
Odds ratios compare the odds of the outcome in an exposed group with the odds of the same outcome in an unexposed group. Odds tell us how likely it is that an event will occur compared to the likelihood that the event will not happen. Odds of 1:3 that an event occurs, e.g. that a horse wins in a race, means the horse will win once and lose three times (over four races). Odds ratios are a way of comparing events across groups who are exposed and those who aren't.

A preparation (as morphine, heroin, and codeine) containing or derived from opium and tending to induce sleep and to alleviate pain; a synthetic drug capable of producing or sustaining addiction similar to that characteristic of morphine and cocaine; a narcotic or opioid peptide

Odds Ratio (OR): The ratio of the odds of an event in the experimental (intervention) group to the odds of an event in the control group. If 100 persons have an event rate of 0.20, then 20 persons have the event and 80 persons do not. The OR will be 20/80 or 0.25. Value 1.00 indicates no differences between the two groups.

An odds ratio is one of several ways to summarise the association between an exposure and an outcome, such as a disease. (Another commonly used approach is to calculaterelative risks.)
Odds ratios compare the odds of the outcome in an exposed group with the odds of the same outcome in an unexposed group. Odds tell us how likely it is that an event will occur compared to the likelihood that the event will not happen. Odds of 1:3 that an event occurs, e.g. that a horse wins in a race, means the horse will win once and lose three times (over four races). Odds ratios are a way of comparing events across groups who are exposed and those who aren't.

Chronic disease of the oral cavity characterised by the progressive build up of constricting bands of collagen in the cheeks and adjacent structures of the mouth. It can cause problems with speech and swallowing and severely restrict mouth opening and tongue movement.

An appliance used to move teeth as part of orthodontic treatment. Examples include: - Fixed appliances (braces where the components are attached to the teeth for the duration of the treatment); - Removable appliances (braces that can be removed from the mouth for cleaning during treatment); - Functional appliances (braces that aim to move the teeth and modify the growth of the jaws. They can either be removable from the mouth or fixed to the teeth during treatment).

Surgical correction of severe malocclusion, in which development of one or both jaws is abnormal, to improve facial appearance. It needs to be carried out in combination with orthodontic treatment and may involve surgery to one or both jaws.

Obstructive sleep apnoea. A condition where partial blockage to breathing in the mouth and at the back of the throat leads to short periods of interruption of breathing while asleep. Such breathing while asleep is noisy, as in snoring

Consist of a number of special titanium alloy inserts, placed in the jawbone, onto which abutments (support for an artificial tooth) are fitted after the bone has healed. Later an artificial-tooth superstructure is attached to the abutments.

A general term referring to any operation in which an artificial opening is formed between two hollow organs or between one or more such viscera and the abdominal wall for discharge of intestinal contents or urine. An incised opening which is kept open for drainage from a hollow organ. Preterm (for example colo-stomy) refers to which part of the intestine the ostomy is performed.

hereditary / familial disorder in which an overgrowth of the bone of the inner ear leads to a fixation of the small bone that normally transmits sound to the inner ear, making sound transmission impossible

Screening detects very early lesions. It is possible that some detected cancers would not affect a person in his or her lifetime (the person remaining asymptomatic and dying from some other cause). Because these cancers are more likely to be found in a screened group rather than an unscreened group, comparisons of outcome might favour the screened group, irrespective of any real effect of screening.

P

The p-value is a measure of the probability or likelihood that a given effect or event will take place by chance. The smaller the value the more likely that the intervention is responsible for an observed effect.

The p-value is a measure of the probability or likelihood that a given effect or event will take place by chance. The smaller the value the more likely that the intervention is responsible for an observed effect.

A drug opposing the effects of the parasympathetic nervous system. The parasympathetic nervous system is one of the two divisions of the autonomic nervous system. It increases bodily secretions such as tears, gastric juices, mucus and saliva to defend the body and help digestion.

A drug opposing the effects of the parasympathetic nervous system. The parasympathetic nervous system is one of the two divisions of the autonomic nervous system. It increases bodily secretions such as tears, gastric juices, mucus and saliva to defend the body and help digestion.

works consisting of a handout or self-contained informative material used to explain a procedure or a condition or the contents of a specific article in a biomedical journal and written in non-technical language for the patient or consumer.

Patient-controlled analgesia. Pain relief with intravenous administration of narcotic analgesics, where the rate of administration is under the patient’s control. A delivery system is programmed so that overdoses cannot be given.

The process of sending articles reporting the outcomes of studies to ‘peers’ for review and comment. It is believed that the peer-review process is a useful quality control activity. In the Cochrane context ‘peer review’ refers to the process of critiquing a protocol or review. It is undertaken by fellow researchers, statisticians, health professionals or consumers. Studies that are not of sufficient quality will not be published if their faults are not corrected. Journals that use peer review are considered to be of better quality than those which do not.

Also known as cognitive assessment or screening tests. These type of tests cannot diagnose dementia as they test limited domains of cognition. They can be useful in identifying someone needing further investigation and are also useful if done serially to map any change in cognition over time.

An area of relative darkness on a radiograph adjacent to the roots of the tooth, due to increased absorption of the x-ray beam. It is commonly associated with the loss of bone density as a result of infection or other pathological (disease) processes.

Person years describes the accumulated amount of time that all the people in the study were being followed up. So, if five people were followed up for ten years each, this would be equivalent to 50 person-years of follow up. Sometimes the rate of an event in a study is given per person year rather than as a simple proportion of people affected, to take into account the fact that different people in the study may have been followed up for different lengths of time.
Person years describes the accumulated amount of time that all the people in the study were being followed up. So, if five people were followed up for ten years each, this would be equivalent to 50 person-years of follow up. Sometimes the rate of an event in a study is given per person year rather than as a simple proportion of people affected, to take into account the fact that different people in the study may have been followed up for different lengths of time.

muscular tube serving as passageway for air from the nose and mouth, and for food and liquid. The part of the pharynx involving the nose is referred to as NASOPHARYNX, the part extending from the mouth to the top of the larynx is called the OROPHARYNX, and the lowermost part is called the HYPOPHARYNX or LARYNGOPHARYNX.

Phase I trials are the early phases of drug testing in humans. These are usually quite small studies which primarily test the drug’s safety and suitability for use in humans, rather than its effectiveness. They often involve between 20 and 100 healthy volunteers, although they sometimes involve people who have the condition that the drug is aimed at treating. To test the drug’s safe dosage range, very small doses are given initially and are gradually increased until the levels suitable for use in humans are found.
These studies also test how the drug behaves in the body, examining how it is absorbed, where it is distributed, how it leaves the body and how long it takes to do this.

During this phase of testing, a drug’s effectiveness in treating the targeted disease in humans is examined for the first time and more is learnt about appropriate dosage levels.
This stage usually involves 200 to 400 volunteers who have the disease or condition that the drug is designed to treat. The drug’s effectiveness is examined and more safety testing and monitoring of the drug’s side effects are carried out.

In this phase of human testing of treatments, the effectiveness and safety of the drug undergoes a rigorous examination in a large, carefully controlled trial to see how well it works and how safe it is. The drug is tested in a much larger sample of people with the disease or condition than before, with some trials including thousands of volunteers. Participants are followed up for longer than in previous phases, sometimes over several years.
These controlled tests usually compare the new drug’s effectiveness with either existing drugs or a placebo. These trials are designed to give the drug as unbiased a test as possible to ensure that the results accurately represent its benefits and risks. The large numbers of participants and the extended period of follow-up give a more reliable indication of whether the drug will work and allows rarer or longer-term side effects to be identified.

The organ that grows in the uterus with the developing baby and provides a connection with the mother, so that oxygen, carbon dioxide, and other nutrients and waste products can be exchanged between the mother’s and baby’s bloodstreams.

An organised screening of large groups of people - also described as 'mass screening'. Population screening differs from opportunistic screening, in which tests are offered on an ad-hoc basis to certain individuals of the population.

This is one of a set of measures used to show how accurate a diagnostic test is (see sensitivity, specificity and negative predictive value). The positive predictive value (PPV) of a test is how well the test identifies people who have a disease. The PPV is the proportion of people with a positive test result who truly have the disease. For example, if a test has a PPV of 99%, this means that 99% of the people who test positive will have the disease, while 1% of those who test positive will not have the disease (false positives).
The PPV of a test varies depending on how common the disease is in the population being tested. A test’s PPV tends to be higher in populations where the disease is more common and lower in populations where the disease is less common.

The probability that a specified difference between control and intervention groups will be significant at a designated significance level, typically 5%, affected by the number of participants in a study such that larger studies have more power.

These are in vitro (for example, in cell cultures) and in vivo laboratory animal tests on drugs in development, which are carried out to ensure that they are safe and effective before they go on to be tested in humans (clinical studies).

The administration of medication to a patient before anaesthesia. This medication may include drugs to relieve pain, sedatives, anti-emetics, or specific treatments, as well as the patient’s normal medication(s).

Or a pressure ulcer: Area of inflamed skin/broken skin, caused by excessive or prolonged pressure shear or friction. This prevents adequate blood flow to the skin and finally the death of skin and underlying tissues

Prevalence describes how common a particular characteristic (for example, a disease) is in a specific group of people or population at a particular time. Prevalence is usually assessed using a cross sectional study.

The act or art of foretelling the course of a disease; the prospect of survival and recovery from a disease as anticipated from the usual course of that disease or as indicated by special features of the case

Difficulty in recognising faces can be quite a common symptom of dementia. This can be very stressful for the individual, as he may, for instance, mistake a family member for an unknown intruder. Sometimes a person may be more able to recognise someone by their voice or another aspect of their appearance, such as familiar clothing.

This study identifies a group of people and follows them over a period of time to see how their exposures affect their outcomes. A prospective observational study is normally used to look at the effect of suspected risk factors that cannot be controlled experimentally, such as the effect of smoking on lung cancer.

A prospective study asks a specific study question (usually about how a particular exposure affects an outcome), recruits appropriate participants and looks at the exposures and outcomes of interest in these people over the following months or years.

One of a group of hormone-like substances present in a wide variety of tissues and body fluids. Prostaglandins have many actions; for example, they cause contraction of smooth muscle, dilation of blood vessels, and are mediators in the process of inflammation (aspirin and other pain killers known as NSAIDs act by blocking their production). They are also involved in the production of mucus in the stomach, which provides protection against acid gastric juice; use of NSAIDs reduces this effect and predisposes to peptic ulceration (stomach ulcers), the principal side-effect of these drugs

A branch of dentistry which is involved in the restoration and maintenance of oral function, comfort, appearance, and health of the patient by the replacement of missing teeth or tissues by artificial means.

In the Cochrane context a protocol is an outline of a healthcare question, its relevance, and how reviewers intend to go about answering the question. The process of developing a protocol is aimed at improving the quality of a future review and minimising bias by deciding beforehand the methods, selection criteria and outcomes to be assessed. A protocol is refereed (peer reviewed) and published in The Cochrane Library to invite feedback as to the usefulness of the question and the process as outlined.

Publication bias arises because researchers and editors tend to handle positive experimental results differently from negative or inconclusive results. It is especially important to detect publication bias in studies that pool the results of several trials.

A monitor that measures the saturation or percentage of oxygen in the bloodstream and the heart rate. The sensor probe is a simple wrap-around or peg-like device that is attached to a finger, toe, or earlobe.

A device that determines the oxygen saturation of the blood of an anaesthetized patient using a sensor attached to a finger, yields a computerized readout, and sounds an alarm if the blood saturation becomes less than optimal

Q

QALY means Quality-adjusted life year. Each year of life gained by a health programme is weighed by the value of that year. The weight for a year of good health is 1; the weight for a year of poorer health or disability is less than 1. QALYs are used in comparisons of programmes which yield different levels of improvement in health status.

A brace that is attached by metal rings on the top back teeth which are joined by a metal framework consisting of inner and outer arms with a coil at each corner allowing the appliance and hence top teeth and/or jaw to be expanded.

Qualitative research uses individual in-depth interviews, focus groups or questionnaires to collect, analyse and interpret data on what people do and say. It reports on the meanings, concepts, definitions, characteristics, metaphors, symbols and descriptions of things. It is more subjective than quantitative research and is often exploratory and open-ended. The interviews and focus groups involve relatively small numbers of people.

(QALY), each year of life gained by a health programme is weighed by the value of that year. The weight for a year of good health is 1; the weight for a year of poorer health or disability is less than 1. QALYs are used in comparisons of programmes which yield different levels of improvement in health status.

Quantitative research uses statistical methods to count and measure outcomes from a study. The outcomes are usually objective and predetermined. A large number of participants are usually involved to ensure that the results are statistically significant.

This term is loosely used to refer to randomised controlled trials where the method of allocation to the different groups is not sufficiently rigorous to ensure allocation concealment. These methods include alternate patients and allocating patients by birth dates.

A method based on chance alone by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant.

A study design in which individuals are assigned, by special randomisation techniques, to two or more groups where one group receives the intervention under investigation and the other(s) receives no treatment, a placebo, or a standard intervention.

Or RCTs. A test in which persons in a population are randomly divided into two groups, usually called study group and
control groups. Overall to compare the effect of one intervention to another (or placebo).

This is a study in which people receive all of the treatments and controls being tested in a random order. This means that people receive one treatment, the effect of which is measured, and then 'cross over' into the other treatment group, where the effect of the second treatment (or control) is measured.

A method based on chance alone by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant.

A method based on chance alone by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant.

A study design in which individuals are assigned, by special randomisation techniques, to two or more groups where one group receives the intervention under investigation and the other(s) receives no treatment, a placebo, or a standard intervention.

This is a study in which people receive all of the treatments and controls being tested in a random order. This means that people receive one treatment, the effect of which is measured, and then 'cross over' into the other treatment group, where the effect of the second treatment (or control) is measured.

Means Randomised controlled trials. A test in which persons in a population are randomly divided into two groups, usually called study group and control groups. Overall to compare the effect of one intervention to another (or placebo).

A study design in which individuals are assigned, by special randomisation techniques, to two or more groups where one group receives the intervention under investigation and the other(s) receives no treatment, a placebo, or a standard intervention.

A study design in which individuals are assigned, by special randomisation techniques, to two or more groups where one group receives the intervention under investigation and the other(s) receives no treatment, a placebo, or a standard intervention.

Means 'risk difference'. The absolute difference in the event rate (see definition) between two comparison groups. An RD of zero incites no differences between the comparison groups. For undesirable outcomes an RD less than zero indicates that the intervention was effective in reducing the risk for that particular outcome.

Recall bias is when a person’s recall of their exposure to a suspected disease risk factor could be influenced by the knowledge that they are now suffering from that particular disease. For example someone who has suffered a heart attack may recall having a highly stressed job. The stress that they now report experiencing may now be subtly different than the stress they would have reported at the time, before they developed the disease.

In the Cochrane context, this refers to the person(s) to whom a protocol or review is sent for critiquing. Referees are usually fellow researchers, statisticians, health professionals or consumers of health care.

In medicine, relapse or recidivism is a recurrence of a past (typically medical) condition.
In dentistry, is the return of the teeth to their initial position after orthodontic treatment with (dental) braces. Unfavourable change from their corrected position.

A measure expressed by the risk of an event in the group receiving the intervention divided by the risk in the control group. A value of one implies no effect of treatment; less than one that the intervention reduced the risk of an event; and greater than one that the occurrence of the event is increased.This measure of risk is often expressed as a percentage increase or decrease, for example ‘a 20% increase in risk’ of treatment A compared to treatment B. If the relative risk is 300%, it may also be expressed as ‘a three-fold increase’.

Also known as 'RR'. The ratio of risk in the intervention group compared to the risk in the control group. The risk is the ratio of people with an event compared to the total in the group. RR value one (1.00) indicates no difference between comparison groups. For undesirable outcomes an RR less than one indicates that the intervention was effective.

A measure expressed by the risk of an event in the group receiving the intervention divided by the risk in the control group. A value of one implies no effect of treatment; less than one that the intervention reduced the risk of an event; and greater than one that the occurrence of the event is increased.This measure of risk is often expressed as a percentage increase or decrease, for example ‘a 20% increase in risk’ of treatment A compared to treatment B. If the relative risk is 300%, it may also be expressed as ‘a three-fold increase’.

Reminyl (galantamine) was co-developed by Shire Pharmaceuticals and the Janssen Research Foundation. Originally derived from the bulbs of snowdrops and narcissi, it was the third drug licensed in the UK specifically for Alzheimer's disease.

The term research means different things to different people, but is essentially about finding out new knowledge that could lead to changes to treatments, policies or care.
The definition used by the Department of Health is: “The attempt to derive generalisable new knowledge by addressing clearly defined questions with systematic and rigorous methods.”

Fills a space in the teeth by using a synthetic (often porcelain) tooth with a backing (usually metal) which extends one or more of the adjacent natural teeth. The backing is bonded to the surface of the adjacent teeth using a modern resin-based adhesive material

A retrospective study relies on data on exposures and/or outcomes that have already been collected (through medical records or as part of another study). Data used in this way may not be as reliable as data collected prospectively as it relies on the accuracy of records made at the time and on people’s recall of events in the past, which can be inaccurate (referred to as recall bias).

In the Cochrane context, this term is used to refer to the authors undertaking a systematic review. In the broader health care context this term refers to a person undertaking a review (assessment for quality relevance etc) of other people’s work.

1. Collate: we gather all published and reported material from around the world, in every language, on any given medical subject.
2. Assess: we review all the research against our rigorous methodological criteria.
3. Synthesise: we analyse and compile the findings of all the scientifically valid studies and create reports that illustrate an intervention's effectiveness.
4. Disseminate: we make the information available in easily digestible summaries, accessible to everyone, on Cochrane Summaries

A way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chances of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events ie common or infrequent.

Criteria used to determine those aspects of a person's condition, lifestyle or environment that increase the probability of occurrence of a disease or condition. For example, pressure ulcer risk assessment scales are used to help predict which people are at high risk of developing a sore and therefore who requires additional treatment to prevent an ulcer.

Also known as RD. The absolute difference in the event rate (see definition) between two comparison groups. An RD of zero incites no differences between the comparison groups. For undesirable outcomes an RD less than zero indicates that the intervention was effective in reducing the risk for that particular outcome.

A measure expressed by the risk of an event in the group receiving the intervention divided by the risk in the control group. A value of one implies no effect of treatment; less than one that the intervention reduced the risk of an event; and greater than one that the occurrence of the event is increased.This measure of risk is often expressed as a percentage increase or decrease, for example ‘a 20% increase in risk’ of treatment A compared to treatment B. If the relative risk is 300%, it may also be expressed as ‘a three-fold increase’.

Means 'relative risk'. The ratio of risk in the intervention group compared to the risk in the control group. The risk is the ratio of people with an event compared to the total in the group. RR value one (1.00) indicates no difference between comparison groups. For undesirable outcomes an RR less than one indicates that the intervention was effective.

A measure expressed by the risk of an event in the group receiving the intervention divided by the risk in the control group. A value of one implies no effect of treatment; less than one that the intervention reduced the risk of an event; and greater than one that the occurrence of the event is increased.This measure of risk is often expressed as a percentage increase or decrease, for example ‘a 20% increase in risk’ of treatment A compared to treatment B. If the relative risk is 300%, it may also be expressed as ‘a three-fold increase’.

A measure expressed by the risk of an event in the group receiving the intervention divided by the risk in the control group. A value of one implies no effect of treatment; less than one that the intervention reduced the risk of an event; and greater than one that the occurrence of the event is increased.This measure of risk is often expressed as a percentage increase or decrease, for example ‘a 20% increase in risk’ of treatment A compared to treatment B. If the relative risk is 300%, it may also be expressed as ‘a three-fold increase’.

The stages of an organised approach to screening. These include identification and invitation the eligible population on a regular basis among other factors. The pathway also includes monitoring and evaluation of all of these stages.

In the Cochrane context, this refers to the way a search is carried out to identify publications or reports that are relevant to a review process. Bias can be minimised and the quality of the review improved by the thoroughness of the search.

A secondary analysis is when researchers revisit data that was collected for a different reason and analyse it again to answer a new research question. This type of analysis is sometimes prone to errors.

In the Cochrane context, this refers to criteria which set out the types of healthcare studies, participants, interventions and outcomes that determine which studies are to be included in a systematic review. This helps review authors search for and identify studies and is aimed to minimise bias.

This is one of a set of measures used to show the accuracy of a diagnostic test (see specificity, negative predictive value and positive predictive value). Sensitivity is the proportion of people with a disease who are correctly identified as having that disease by the diagnostic test. For example, if a test has a sensitivity of 90%, this means that it correctly identified 90% of the people with the disease, but missed 10% (these people were ‘false negatives’ on the test).

A determination of the reliability of a result by assessing confounders or influencing factors that may affect the outcomes measured. This may be done by repeating statistical analyses leaving out poorer quality studies or studies with relevant differences in the characteristics of the participants for example.

A general term usually used to denote the three types of growths in the skin. The commonest type is basal cell carcinoma, or rodent ulcer, followed by squamous cell carcinoma and finally by the much rarer melanoma. Basal cell carcinoma doesn't spread and virtually never kills people. Squamous cell carcinoma can occasionally spread to lymph nodes and other organs. Melanoma if caught early is curable, but if it has spread deep down into the skin and blood stream, it can spread to other organs of the body like other cancers

support systems that provide assistance and encouragement to individuals with physical or emotional disabilities in order that they may better cope. Informal social support is usually provided by friends, relatives or peers, while formal assistance is provided by churches, groups, etc.

This is one of a set of measures used to assess the accuracy of a diagnostic test (see sensitivity, negative predictive value and positive predictive value). Specificity is the proportion of people without a disease who are correctly identified as not having that disease by the diagnostic test. For example, if a test has a specificity of 95%, this means that it correctly identified 95% of the people who did not have the disease, but that 5% of people without the disease were incorrectly diagnosed as having the disease (these people were ‘false positives’ on the test).

The process of examining collected numerical measurements in order to determine if they are a fair representation of a situation, what value or significance can be given to them, and consequently the size and numerical significance of an intervention effect.

If the results of a test have statistical significance, it means that they are not likely to have occurred by chance alone. In such cases, we can be more confident that we are observing a ‘true’ result.

If the results of a test have statistical significance, it means that they are not likely to have occurred by chance alone. In such cases, we can be more confident that we are observing a ‘true’ result.

When participants of a study are further divided according to factors other than the intervention received eg age, sex, severity of disease or physical condition, dose of intervention or quality of study.

This is a synthesis of the medical research on a particular subject. It uses thorough methods to search for and include all or as much as possible of the research on the topic. Only relevant studies, usually of a certain minimum quality, are included.

This is a synthesis of the medical research on a particular subject. It uses thorough methods to search for and include all or as much as possible of the research on the topic. Only relevant studies, usually of a certain minimum quality, are included.

Time trend studies are epidemiological studies that describe characteristics of a population over time. They look at trends at the population level (rather than in individuals) through taking repeated cross sectional samples.

In the Cochrane context this refers to the topic of a review. Cochrane titles have a set structure: intervention for an identified health issue (and sometimes in which population). This facilitates finding reviews using The Cochrane Library search mechanism.

Clinical trials are research studies involving people who use services, which compare a new or different type of treatment with the best treatment currently available. They test whether the new or different treatment is safe, effective and any better than what already exists. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known.

Twin studies rely on comparing the phenotypes (observable physical traits) of monozygotic (genetically identical) twins and dizygotic (non-identical) twin pairs. The difference in correlation between phenotypes in the identical twins and the correlation in phenotypes in the non-identical twins estimate the genetic contribution to variations in phenotype (the within-twin correlation).

Vascular dementia is the second most common form of dementia after Alzheimer's disease. It is a type of dementia caused by problems in the supply of blood to the brain. There are two main types of vascular dementia: one caused by stroke and one caused by small vessel disease. Vascular dementia affects different people in different ways and the speed of the progression varies from person to person. Some symptoms may be similar to those of other types of dementia. However, people with vascular dementia may
particularly experience:
• problems concentrating and communicating
• depression accompanying the dementia
• symptoms of stroke, such as physical weakness or paralysis
• memory problems (although this may not be the first symptom)
• a 'stepped' progression, with symptoms remaining at a constant level and then suddenly deteriorating
• epileptic seizures
• periods of acute confusion.
Other symptoms may include:
• hallucinations (seeing things that do not exist)
• delusions (believing things that are not true)
• walking about and getting lost
• physical or verbal aggression
• restlessness
• incontinence.
[adapted from Alzheimer’s Society website]

sensation of either the individual or the surroundings being in constant motion (especially spinning) caused by a disorder of the balance organ in the inner ear or by a disorder in the neural conduction of balance information to the brain

the two folds of tissue protruding from the sides of the LARYNX to form a narrow slit (GLOTTIS) across the air passage. Their controlled interference with the expiratory air flow produces audible vibrations that make up speech, song, and other vocal noises.

Giving more value to the data from one study over another when pooling data to carry out a meta-analysis. This may be because the study has a greater number of participants, is more precise in the measure for intervention effect (the value has lower standard deviations), or that more healthcare events occurred.